Dynamoelectric machine



Sept. 18, 1945. A. F HER 2,385,199

DYNAMOELECTRIG MACHINE Filed Dec. 8, 1944 2 Sheets-Sheet 1 FiSgJ.

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r "'1 l I 14 I5 I I6 I L 1 l' Inventor:

Alec Fisher Sept. 18, 1945- A. FISHER DYNAMOELECTRIC MACHINE Filed Dec.8, 1944 2 Sheets-Sheet 2 Fig.5.

VIII

Inventor. Alec Fishe Hrs Attorney.

Patented Sept. 18, 1945 DYNAMOELECTRIC MACHINE Alec Fisher, Lynn, Masa,asslgnor to General Electric Company, a corporation of New YorkApplication December 8, 1944, Serial No. 567,209

11 Claims.

My invention relates to dynamoelectric machines and particularly to agenerator for generating alternating current and direct current using asingle field structure and a single rotatable member.

An object of my invention is to provide an improved dynamoelectricmachine for generating alternating current and direct current in thesame rotatable member with a single field structure.

Further objects and advantages of my invention will become apparent andmy invention will be better understood from the following descriptionreferring to the accompanying drawings, and the features of noveltywhich characterize m invention will be pointed out with particularlityin the claims annexed to and forming part of this specification.

In the drawings, Fig. 1 is a schematic illustration of a dynamoelectricmachine provided with an embodiment of my invention; Fig. 2 is a curveillustrating the flux distribution of the pole pieces forming the fieldstructure of the machine shown in Fig. 1; and Fig. 3 is a schematicillustration of a dynamoelectric machine provided with anotherembodiment of my invention.

Referring to the drawings, I have shown in Fig. 1 a dynamoelectricmachine provided with an embodiment of my invention in which a singlefield structure is provided for a single rotatable member having'twowindings, in one of which an alternating current is adapted to beinduced, and in the other of which a direct current is adapted to beinduced. In this structure, the rotatable member i is provided with analte nating current rotor winding 2 connected to collector rings 3, fromwhich alternating current is adapted to be connected to any desired loadby collector brushes l connected to terminal leads 5. The rotatablenimber also is provided with a direct current armature winding 6connected to a suitable commutator l which forms an electrical contactwith collector brushes 8 and 9 which are connected to the direct currentterminals l and II of the machine through suitable field excitingwindings which are provided on the stationary member of the machine.This stationary member forms the field structure of the machine andincludes a magnet frame l2 provided with suitable polar projections forforming the magnetic poles of the machine. These polar projections areillustrated as comprising four main salient pole pieces 13, i4, i5, andi6 and a pair of commutating pole pieces I! and I8. The voltage inducedin an armature winding is dependent upon the total flux which is cut bythe winding between the brushes which include each set or pair of polesoi the machine. In the illustrated construction, the poles for thedirect current armature winding 6 are formed by two salient pole piecesfor each pole. The drawing illustrates a two-pole D.-C. machine;however, any multiple of this combination can readily be used by merelymultiplying the fleld arrangement and the sets 01 brushes shown in thedrawing. The direct current armature excitation is provided by a singlepair of poles iormed by the two pole pieces II and I4 and the two polepieces It and il excited by a field exciting winding including coils I!and 20 on the pole pieces l3 and II which provide an excitation asindicated by the arrows 2i and 22 and by coils I3 and 24 which providecomponents of excitation to the pole pieces i5 and It, as indicated bythe arrows 2i and 26, respectively. This provides a resultant poleformed by the pole pieces II and I4 and another resultant pole formed bythe pole pieces II and II, providing the desired excitation for thedirect current armature winding 6.

In order to operate the machine at a reasonable speed irom a mechanicalstandpoint and yet obtain the desired frequency from the alternatingcurrent rotor winding 2, it is desirable that the alternating currentfield excitation should have a larger number of poles than the directcurrent excitation system. Since the voltage between the direct currentbrushes 8 and 9 is dependent only upon the total flux cut by thearmature windings between these brushes, it is possible to provideanother component of excitation to the pole pieces of the machine toform a four-pole excitation for the alternating current winding withoutchanging the total flux cut by the direct current winding between thebrushes 8 and 9, providing the saturation eilects of the machine areminimized. In order to minimize the eifects of saturation on themachine. a slightly oversize stationary member field structure isprovided. The field excitation for the alternating current rotor winding2 is provided by a field exciting winding including coils 27, 28, 29,and iii arranged on the salient pole pieces i3, ll, i6, and i6,respectively, to provide components of excitation thereto as indicatedby the arrows 3|, 32. 33, and 34, respectively, which providesuccessively opposite polarity compounds of excitation to each of thepole pieces.

The net excitation provided by each of the pole pieces is illustratedgraphically in Fig. 2, in which the net or resultant excitation for thediflercnt pole pieces is shown by the solid line 35, the direct currentarmature excitation component 01' excitation is indicated by the dottedline 36, and the excitation provided by the field exciti ll winding torthe alternating current rotor winding is shown by the dot-and-dash lines31. The diflerent components of excitation and the resultant excitationfor each or the pole pieces is indicated by the numbers l3, ll, II, andl! which correspond to the components or excitation provided by thesalient pole pieces ll, ll, l5, and Win Fig, 1. Thus, it is seen thatthe total direct current armature excitation provided to the winding 6by the pole ieces I8 and It remains the same even though the resultantexcitation of the pole piece II is increased by the component oiexcitation provided by the coil 21, and the excitation of the pole pieceII is diminished by the excitation provided by the coil II. Similarly,the net excitation provided by the ole pieces I! and It to the directcurrent. armature winding 6 remains unchanlled, although the netexcitation provided by the pole piece II is diminished by the excitationcomponent provided by the field coil 20, and the net excttltion of thepole piece I8 is increased by the component of excitation provided bythe field coll II. Similarly, the frequency of the alternating currentinduced in the alternating current winding I has the same value as itthe component of excitation provided by the winding tor the directcurrent armature excitation were entirely omitted. It is clear,therefore, that either of the excitation systems may be varied at willwithout providing any substantial net or resultant eflect on theexcitation system of the other windin: of the rotatable member. Thesecontrol variations may be provided for in any suitable manner, as byvariable resistors 38 and I! connected to the sources of electricalpower supply which enerlln the two field exciting windings described.

In order to improve the independence of the two windings oi therotatable member, I provide a compensating field exciting windingarrangement including coils 40 and ll connected to the brushes 8 and 5through commutating ileld exclting windings l2 and it. Thesecompensating field exciting windings l0 and II are adapted to provide acomponent of excitation, as indicated by the arrows 44, whichsubstantially neutralize armature reaction resulting from current in thedirect current armature winding 0, such that this component of armaturereaction has substantially no effect on the excitation provided to thealternating current rotor winding I. In order to improve the commutationof the direct current armature winding, the commutating field excitingwinding coils l2 and I are arranged to provide components oi excitationas indicated by the arrows 45, as in a conventional direct currentmachine. In order to minimize the eilect oi. this commutatim componentor excitation on the alternating current rotor winding 2, thecommutating salient pole pieces I! and II are formed with a slightlylarger air gap than that o! the main pole pieces of the machine. Thecompensating field exciting winding and the commutatin field excitingwinding are connected in series with the direct current brushes I and Oand are, therefore, directly responsive to the variations in the directcurrent in the armature winding I and provide the desired compensatingand commutating components of excitation tor this winding. irrespectiveoi the alternating current which may be induced in the alternatingcurrent winding 2, and minimize the eflects oi armature re- KID actionupon the alternating current rotor wind- In Fig. 3, I have shown anotherembodiment of my invention in which both of the control components ofexcitation are provided to the pole pieces by a single ileld excitingwinding energized by two separate sources of energimtlol which can becontrolled independently of each other to provide the two components ofexclt tion to the pole pieces in the same manner as that shown in Fig.1, providing the same resultant or net component of excitation as shownby thegraphinFlg.2. Inthisconstructlomaaln the machine shown in Fig. l,the rotatable memper i is provided with an alternating current notingcurrent The rotatable member also is direct current armature windim Iconnection to a conventional direct current commutator T and is providedwith direct current collector brushes landloonnectedtothedirectcurrentleads ll and II through fleld excitlna aimilsrtothoseshown lung. 1.Intbisarrangement, a single control field exciting winding is adapted toprovide the excitation to the atasalient pole pieces l3. eludes excitingcoils l0, .1, 4|, and l, reopen-.- tlveiy, which are adapted to beenergised by a com onent. or energiaation provided by a source ofelectrical power supply II to provide a component of excitation to thepole pieces, as inficated by the arrows Ii and II, to the ileid polepieces I! and Il and, as lndicatedbythe arrow l8 and ll, to the salientpole pieces II and It, respectively, than providing a single pair atresultant poles 102' this component or excltattm. in the same manner asthat shown in the previour construction. A second source of magmation Iiis connected to the field excitlni winding coils 40, ll, ll, and I! atthe inte intermediate the connections of these coils to the source ofenergization a, so as to provide a second component of energizatlon tothese coils which will provide a component of excitation to the salientpole pieces II, II, ll, and II. as indicated by the arrows i, ll, SI,and II; which are alternately of opposite polarity in adiacent polepieces. thereby providing tour poles by this component of excitationwhich rom the desired excitation imthe alternaflhl current motor windingI. Thus, the encltatlon pro-- vided tothedimctcunent armature windin tby the single pair oi poles may be indicated in Pig. 2 by the dottedline. and the excitation provided by the four component poles ofexcitation by the component or excitation provided by the source ofenergiaation I! maybe represented by the dot-and-dash line if in thisfigure, with the resultant or net excitation of the pole piecesrepresented by the solid line a in this figure, which is the same asthat replie tented for Fig. l. with this arrangement. as in the arranement in vided by the exciting winding energised item the source ofenerglzation I torcontrolling the alternating current in the rotorwinding 1 is cumulative with respect to the component oi excitationprovided by the energizatlon for providing excitation for the directcurrent armature winding I in alternate pole pieces and is diflerentialwith respect thereto in the other pole pieces.

Fig. '1, the excitation pro- As in the arrangement shown in Fig. l, thedirect current brushes 8 and 9 are connected to a compensating windinghaving coils l and U and to a commutating winding having cogs l2 and 43providing components of excitatio l4 and 45, respectively, forsubstantially neutralizing armature reaction due to direct current inthe armature winding 6 and for providing the desired commutatingcomponent of excitation as in a conventional machine, respectively. Thecommutating salient pole pieces II and i8 also are formed with arelatively larger air gap than the main pole pieces in order to minimizetheir efi'ect on the alternating current rotor winding 2. The twocomponents of energization provided to the main control field excitingwinding may be controlled independently oi each other in the same manneras in Fig. l by the provision of variable resistors 60 and SI forindependently controlling these two components oi energize.- tion. As inthe construction shown in Fig. 1, this arrangement provides for theindependent control of the alternating and direct currents generated bythe machine without materially affecting the other typ of currentgenerated by the machine by the provision of a relatively largermagnetic circuit to minimize the efi'ects oi saturation on the magneticexcitation of the machine.

While I have illustrated and described particular embodiments of myinvention, modifications thereof will occur to those skilled in the art.I desire it to be understood, therefore, that my invention is not to belimited to the particular arrangements disclosed, and I intend in theappended claims to cover all modifications which do not depart from thespirit and scope or my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having means for magnetically field exciting saidstationary member arranged to provide a resultant component pair ofmagnetic field poles thereto for exciting said direct current armaturewinding, and means for providing a second component of excitation tosaid stationary member for providing two component pairs of magneticfield poles providing a component of magnetic excitation cumulative withsaid first-mentioned field excitation to alternate poles of said secondfield poles an a component or magnetic excitation differential with saidfirst-mentioned field excitation to the other of said second field polesfor exciting said alternating current rotor winding.

2. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member havin means for magnetically exciting said stationarymember arranged to provide a resultant component set of magnetic fieldpoles thereto for exciting said direct current armature winding, andmeans for providing a second component of excitation to said stationarymember for providing a multiple or said component set of magnetic fieldpoles providing a component of magnetic excitation cumulative with saidfirst-mentioned field poles to alternate of said second component polesand a component of magnetic excitation diiiarential with said firstfield poles to the other of said secand component poles for excitingsaid altemating current rotor winding.

3. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having four pole pieces, means for magneticallyexciting said pole pieces arranged to provide a resultant component pairof magnetic field poles thereto for exciting said direct currentarmature winding, and means for providing a second component ofexcitation to said pole pieces for providing two component pairs ofmagnetic field poles by said pole pieces providing a component ofmagnetic excitation cumulative with said first-mentioned field excitingwinding to alternate of said pole pieces and a component of magneticexcitation differential with said first field exciting winding to theother oi said pole pieces for exciting said alternating current rotorwinding,

4. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having four pole pieces and a field exciting windingarranged to provide a resultant pair of magnetic field poles thereto,and a second field exciting winding arranged to provide two pairs ofmagnetic field poles by said pole pieces and providing magneticexcitation cumulative with said first-mentioned field exciting windin toalternate of said pole pieces and magnetic excitation diflerential withsaid first field exciting winding to the other of said pole pieces.

5. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having means for magnetically exciting said stationarymember arranged to provide a resultant component set or magnetic fieldpoles thereto for exciting said direct current armature winding, meansfor providing a second component of excitation to said stationary memberfor providing a multiple of said component set 01' magnetic field polesproviding a component of magnetic excitation cumulative with saidfirst-mentioned field poles to alternate of said second component polesand a component of magnetic excitation differential with said firstfield poles to the other of said second component poles for excitingsaid alternatingcurrent rotor winding, and means including acompensating field exciting winding energized responsive to current insaid direct current armature winding and arranged to provide a resultantcomponent of magnetic excitation in opposition to armature reactionproduced by current in said direct current armature windin forsubstantially neutralizing said armature reaction.

6. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having means including a field exciting windingarranged and having a component of energization to provide a resultantcomponent pair of magnetic field poles thereto for exciting said directcurrent armature winding, and means fo providing a second component ofonergization to said field exciting winding arranged to provide twocomponent pairs of magnetic field poles providing a component ofmagnetic excitation cumulative with said first-mentioned field excitingwinding component of energization t alternate of said second componentpoles and a component of magnetic excitation differential with saidfirst field exciting winding component of energization on the other ofsaid second component poles.

'7. A dynamuelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having four pole pieces, means including a fieldexciting winding arranged and having a component of energizatlon toprovide a resultant component pair of magnetic field poles thereto forexcitingsald direct current armature winding. and means for providing asecond component of energlzation to said field exciting winding arrangedto provide two component pairs of magnetic field poles by said polepieces providing a component of magnetic excitation cumulative with saidfirst-mentioned field exciting winding component of energization toalternate of said pole pieces and a component of magnetic excitat ondifferential with said first field exciting winding component ofenergization to the other of said pole pieces.

8. A dynamoeiectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto. and astationary member having four pole pieces, means for magneticallyexciting said pole pieces arranged to provide a resultant component pairof magnetic field poles thereto for exciting said direct currentarmature winding, means for providing a second component of excitationto said pole leces for providing two component pairs of magnetic fieldpoles by said pole pieces providing a component of magnetic excitationcumulative with said first-mentioned field exciting winding to alternateof said pole pieces and a component oi magnetic excitation differentialwith said first field exciting winding to the other of said pole pieces,and means including a compensating field exciting winding energizedresponsive to current in said direct current armature winding andarranged to provide a resultant component of magnetic excitation inopposition to armature reaction produced by current in said directcurrent armature winding for substantially neutralizing said armaturereaction.

9. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature wind ng and a commutator connected thereto and an alternating crrent rotor winding with collector rings connected thereto, and astationary member having a field exciting winding arranged to provide aresultant component pair of magnetic field poles thereto, a second fieldex citing windllig arranged to provide two component pairs of magneticfield poles providing a magnetic excitation cumulative with saidfirstmentioned field exciting winding to alternate oi said second fieldpoles and magnetic excitation differential with said first fieldexciting winding to the other of said second field poles, and meansincluding a compensating field exciting winding energized responsive tocurrent in said direct current armature winding and arranged to providea resultant component of magnetic excitation in opposition to armaturereaction produced by current in said direct current armature winding forsubstantially neutralizing said armature reaction.

10. A dynamoelectric machine for generating alternating current anddirect current including a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having four pole pieces and a field exciting windingarranged to provide a resultant pair of magnetic field poles thereto. a.second field exciting winding arranged to provide two pairs of magneticfield poles by said pole pieces and providing magnetic excitationcumulative with said first-mentioned field excitin winding to alternateof said pole pieces and magnetic excitation diflerential with said firstfield exciting winding to the other of said pole pieces, and meansincluding a compensating field exciting winding energized responsive tocurrent in said direct current armature winding and ar ranged to providea resultant component of magnetic excitation in opposition to armaturereaction produced by current in said direct current armature winding forsubstantially neutralizing said armature reaction.

11. A dynamoelectrlc machine for generating alternating current anddirect current includin a rotatable member having a direct currentarmature winding and a commutator connected thereto and an alternatingcurrent rotor winding with collector rings connected thereto, and astationary member having four pole pieces and a field exciting windingarranged to provide a resultant pair of magnetic field poles thereto, asecond field exciting winding arranged to provide two pairs of magneticfield poles by said pole pieces and providing a magnetic excitationcumulative with said first-mentioned field exciting windlng to alternateoi said pole pieces and magnetic excitation difierentlal with said firstfield exciting winding to the other of said pole pieces, means includinga commutating field exciting winding for providing commutatingexcitation between said resultant pair of magnetic field poles for saiddirect current armature winding, and means including a compensatingfield exciting winding energized responsive to current in said directcurrent armature winding and arranged to provide a resultant componentof magnetic excitation substantially along the direct currentcommutating pole axis in opposition to armature reaction produced bycurrent in said direct current armature winding for substantiallyneutralizing said armature reaction.

ALEC FISHER.

CERTIFICATE OF CORRECTION. Patent No. 2,385,199. September 1 191 A F1BHEH.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,sec-- 0nd column, line 50 for "compounds" read --components-; and thatthe Said Le tter-s Pa tent should be read with this correction thereinthat the same may conform to 'the record of the case in the PatentOffice.

Signed and sealed this 25th day of December, A. D. 19115.

Leslie Frazer (Seal) First Assls tent Commissioner of Patents.

